Electrical furnace



Oct. 3l, 1933. J. T. NlcHbLs ELECTRICAL FURNACE Filed ocx. fr, 1932 /7/3 Wa/Wega [Qwed'o: JOHN 7i /V/CHOLS,

Patented oet. 31, 1933v UNITED STATES ELECTRICAL FURNACE John T. Nichols, Pittsburgh, Pa., assigner to American Sheet and Tin Plate Company, a corporation of New Jersex1 Application October 7, 1932. Serial Nei-.636,736

3 Claims.

Thisy invention relates to electrical furnaces heated by resistance bars mounted by terminal bars arranged in holes in the furnace structure, one of the objects being to prevent the passage of 5 gases around these terminal bars.

' It is necessary to renew such heating resistance bars when they become disabled through usel or accident and, as this necessitates the removal of the terminal bar, it is necessary that the invention effect such sealing by a readily removable means, this being a second object. Other objects than the above may be inferred from the following illustrative example o'f the invention.

Referring to the drawing: l

Figure l is a vertical cross-section of a furnace portion. Y

Figure 2 is an end elevation. Figure 3 is an enlargement from Figure 1. No attempt ,has been made to'illustrate a complete furnace, it being deemed sufficient to show only its wall 1a terminal hole 2, the terminal bar 3 and thefe'nd of a heating resistance bar 4. The terminal bar 3 engages and mounts the resistance bar 4 and has an externally projecting shouldered end 3*. vThe end 3* is engaged by current conducting mechanism in the conventional manner. The terminal bar itself is of the usual water cooled variety fitting loosely in the hole, and the entire assembly asso far described 3o' is well known to any one familiar with these furnaces.

The resistance bar 4 expands 'and contracts when its temperature changes and moves the terminal bar accordingly.- Any means which is to seal the space between the terminal bar 3 and the hole in the furnace wall must be suiiiciently flexible to accommodate this movement.

According to the present invention a metallic bellows 5 encircles the projecting end o! the ter- 40 minal bar 3. This bellows is provided with an aiilxed inwardly extending end 6 which fits snugly around the terminal bar and engages the shoulder of its end 3E. Here it is held by a nut 7 which is screw-threaded onto the terminal bar, so as to clamplit thereagainst. Preferably, this nut 'is provided with radial grooves 'IEL forengagement by a suitably constructed wrench.

The other end of the bellows 5 is mounted by a refractory and insulating ring 8 which extends outwardly a suihcient distance to engage the outside of the furnaces wall l around the hole 2. This ring may be of asbestos and is clamped to the walls outside by an annular mounting member 9. Preferably this is effected by extending screws 10 which pass through open ended slots ,11 and are provided withwing-nuts 12. The

open ended slots l1 permit the quick removal of the member by partial rotation without requiring the removal. of the wing-nuts.

The above construction effectively prevents the ce escape of gas through the hole 2 around the terminal bar 3 and at the same time provides the requisite flexibility. Should the terminal bar 4 need replacement the wing-nuts 12 are loosened, the annular member 9 given a slight'rota- 65 tion and the terminal bar removed. The end 3B of the terminal bar is screw-threaded in place and its removal permits the disengagement of the bellows 5.

While I have shoywn and described one specific embodiment of my invention it will be understood that I do not wish to be limited thereto, since various modifications may be made without departing from the scopel of the invention as dened in the appended claims.

' I claim:

1. An electrical heating furnace including the combination of a walll having a hole therein, a heating resistance bar arranged in said furnace with its end registering with said hole, a. terminal bar arranged in said hole to engage the end of said resistance bar and with an externally projecting shouldered end, a bellows encircling the projecting end of said lterminal bar and hav ing an inwardly extending end which fits the bars shouldered end, a nut arranged in screwthreaded engagement with said bar and clamping the inwardly extending end of said bellows to the shouldered end of the bar, and means for flxing the other end of said bellows to the outside of said wall in a gas-tight manner.

terminal bar, an annular insulating ring mounting the other end of said bellows and having a diameter permitting it to engage the portions of said wall adjacent said hole', means for clamping the inwardly extending end of said bellows against the shouldered end of said terminal bar,

and removable means for clamping said annular insulating ring to the outside of said wall.

3. An electrical furnace including the combination of a wall having a hole therein, a heating resistance bar arranged in said furnace with an the shouldered end of this bar, a refractory ,and electrically insulating ring fixed to the other end o said bellows and extending outwardly a sutil cient distance to engage the outside of said wall around said liole, and an annular mounting member constructed and arranged to releasably clamp said ring to the outside of said wall.

JOHN T. NICHOLS. 

